Complementary to Maintenance Enhancement Project, CNE-Prod has started in 2003 the development of a Plant Life Management (PLiM) Programme strategy for Cernavoda Unit 1. The programme use approaches that build on PLiM experience at other advanced CANDU and/or PWR Stations from western countries but implementation strategy is specific to Cernavoda Unit 1. The objective is to start early in plant life on systematic ageing management and hence reap benefits during the on-going plant operation, which is expected to be longer than that for the early CANDU plants.

The overall approach adopted is to consider all the issues relating to physical plant ageing as well as “institutional” ageing through an integrated approach. The physical plant assessment focuses on the continuing ability of the structure, system or component to meet the specified performance standards over its design life. If, in spite of maintenance and or refurbishment, a critical structure or component is deemed not likely to be able to meet its performance requirements, then a timely replacement must be undertaken with due consideration to the associated cost-benefits justification.

Figure A. III.1 below, shows the key elements of the life management programme for physical plant, as follows:

• Based on a screening methodology, a set of critical systems, structures and components is identified consistent with meeting the station goals and objectives.

• Life assessment studies are performed for critical structures and components that are generally passive in nature and typically designed not to be replaced as part of normal maintenance programme. The objective is to assess relevant degradation mechanisms and develop an appropriate ageing management plan to achieve design life with the option for life extension.

• Maintenance optimization studies are performed for critical systems with emphasis on active components (that are generally designed to be replaced as part of the normal maintenance programme), in order to preserve the defined systems functions. [8]

• Obsolescence studies are performed on generic plant components that cannot be maintained or refurbished in a cost effective manner due to several factors (such as availability of spares and new developments in technology that make replacement a viable option). Obsolescence relates primarily to instrumentation and control equipment and computer systems.

• Integrated safety and performance assessment is performed with AECL[9] support in order to demonstrate continued compliance with the safety and licensing basis requirements as the plant ages.

•

OPEX programme addresses emerging key issues that may adversely affect plant safety and reliability and may not be addressed by the assessment process described above. This programme relies on monitoring of the operating experience feedback, recent R&D activities, and new developments in regulatory requirements and industry practices.

Fig. A. III.1. Plant life management — Physical plant assessment.

Figure A. III.2 below shows a corresponding block diagram covering the impact of “institutional” ageing. If the management infrastructure is allowed to degrade beyond what are normally accepted industry standards, then the plant will be forced to shutdown until the underlying issues can be resolved in a satisfactory manner. The major initiatives for improvement dealing with institutional ageing included in the station technical programmes schedule are:

• Enhance day-by-day engineering & technical support to plant emerging issues

• Increase technical unit personnel efficiency

• Enhance engineering analysis expertise

• Technical support to Unit 2 commissioning

• Optimize design bases

• Improve design engineering processes

• Improve station governing documents (station policies and procedures)

• Complete implementation of self assessment process

• Optimize data collection & electronic performance indicators reporting

• Upgrade OPEX process

• Optimize corrective actions process

• Improve first line supervisors management skills

Plant Life Management

Fig. A. III.2. Plant life management — Institutional assessment.